1. Field of the Invention
The present invention generally relates to a surveillance method, and more particularly to a surveillance method based on a low power wireless sensor network.
2. Description of Related Art
A video surveillance system uses cameras at major sites to record image information, which is then transmitted via the Internet and is centrally monitored. The video surveillance system takes the place of manpower surveillance, and increases surveillance efficiency.
According to one characteristic of conventional video surveillance systems, the cameras that record image information are powered by mains electricity, and are in active state most of the time. Power wiring complicates the task of setting the cameras, and makes it inflexible to relocate the cameras.
According to another characteristic of the conventional video surveillance systems, one packet is transmitted in each communication session, such that time is wasted and energy efficiency cannot be raised.
A scheme is proposed to modify media access control (MAC) sublayer in order to transmit plural packets in each communication session. However, devices made by different manufacturers may probably be incompatible with each other for communication.
A need has thus arisen to propose a novel surveillance structure in order to overcome disadvantages encountered in the conventional video surveillance systems.